系列甘露糖醛酸寡糖的制备与鉴定

用酸降解法制备了系列甘露糖醛酸寡糖(聚合度2～8),并分析测定了寡糖的结构. 褐藻胶经部分酸水解,于pH=2.85处分级获得聚甘露糖醛酸. 继续用酸降解法降解聚甘露糖醛酸,经凝胶柱层析分离纯化,获得系列甘露糖醛酸寡糖. 用荧光标记糖电泳(FACE)对寡糖进行了分析,并用电喷雾离子化质谱(ESI-MS)、 核磁共振波谱(NMR)及红外光谱(FTIR)进行了结构表征. 本研究用酸降解法制备饱和甘露糖醛酸寡糖,用凝胶柱层析法分离获得系列聚合度的寡糖,为褐藻胶大分子构效关系研究和药物的筛选与发现提供了重要的基础资料.     

几种糖醛酸及其寡糖的薄层层析分析

以葡萄糖醛酸（GlcA）、半乳糖醛酸（GalA）、甘露糖醛酸（ManA）、古罗糖醛酸（GulA）、半乳糖醛酸寡糖（Oligo-GalA）、甘露糖醛酸寡糖（Oligo-ManA）、古罗糖醛酸寡糖（Oligo-GulA）和酶解褐藻胶寡糖（Oligo-u-Alg）为研究对象,探讨其薄层色谱（TLC）行为。结果表明,TLC对不同糖醛酸寡糖有良好的分离和分析效果,其中Oligo-GalA与褐藻胶来源的寡糖兄值不同,而同样来源于褐藻胶的Oligo-ManA与Oligo-GulAR,值相同;首次发现酸解与酶解褐藻胶寡糖聚合度相同时兄值不同。此外,4种糖醛酸对不同的显色剂的显色灵敏度也略有不同,其中硫酸铈显色剂的显色效果最灵敏。这些结果为快速有效分析酸性寡糖的纯度及其聚合度,提供了简便有效的方法。     

低聚褐藻胶合铁（Ⅲ）配合物的制备及性能

通过褐藻胶降解得到低聚褐藻胶,再与FeCl3配合反应制得系列褐藻胶合铁(Ⅲ)配合物. 其配合物易溶于水,在pH＜12时稳定,易被维生素C还原而适宜人体吸收,粘均分子量为21.4和9.8 kDa的低聚褐藻胶合铁(Ⅲ)配合物中铁含量较高,可达约34%. 动物实验表明,喂药6～8 h后血清中铁的浓度明显升高,其生物利用度为1.067.     

海藻酸钠的疏水改性及在药物控释中的应用

海藻酸盐是一种由β-D-甘露糖酸盐(M)和α-L-古罗糖酸盐(G)连接而成的天然高分子,广泛存在于各类棕色海藻中,可与多价阳离子形成凝胶,成胶条件温和,该凝胶在生物体内以酶解方式生成甘露糖醛酸和葡萄糖醛酸,对机体无毒性、无免疫原性,适合作为释放或包埋药物、蛋白质与细胞的微胶囊.     

硒化聚甘露糖醛酸的合成及抗阿尔茨海默症细胞氧化与凋亡

以聚甘露糖醛酸为原料, 采用先磺化、 再硒化的方法合成了硒化聚甘露糖醛酸, 产率为54%, 产物硒含量为437.25 μg/g. 在2.5 μmol/L硒浓度下, 硒化聚甘露糖醛酸促细胞生长能力达到最适范围, 能保护细胞免受过氧化氢损伤, 显著提高阿尔茨海默症(AD)模型细胞N2a-APP695-sw中的超氧化物歧化酶和谷胱甘肽过氧化物酶的活性, 降低细胞内活性氧自由基, 增加线粒体膜电位, 抑制细胞色素C的释放, 在促进Bcl-2表达的同时抑制Bax的表达, 从而具有抑制AD细胞凋亡的功能. 硒化聚甘露糖醛酸也能抑制AD病理相关蛋白BACE1和APP的表达. 结果表明, 硒化聚甘露糖醛酸在抗AD方面具有潜在的应用前景.     

裙带菜中聚甘露糖醛酸的分离纯化与结构分析

以裙带菜(Undaria pinnatifida, wakame)为原料, 经水提醇沉、DEAE-Sepharose Fast Flow、Sephacryl S-300和Sephacryl S-200凝胶柱分离纯化, 得到2个酸性多糖UPPS03和UPPS04. 高效凝胶渗透色谱测试结果表明, 其为均一多糖, 平均分子量分别为3.6×104和1.1×104. 采用糖组成分析、高碘酸氧化及Smith降解、糖醛酸还原、甲基化、红外光谱和核磁共振等方法对该多糖的化学结构进行了表征. 结果表明, 2个多糖均为1,4连接的聚甘露糖醛酸.     

鲍鱼多糖Hal-A的甲醇解研究

从鲍鱼中分离出一种鲍鱼多糖Hal-A，并用改进甲醇解方法研究了Hal-A的组成 ，该多糖甲醇解产物经三甲硅醚衍生后，进行GC/MS，结果表明鲍鱼多糖Hal-A主要 由葡萄糖、半乳糖、甘露糖和少量木糖、岩灌糖和半乳糖醛酸组成。     

对-二苯氨基联二苯基硼酸对单糖的识别研究

本文以二苯基胺和对-二溴联苯合成新型硼酸衍生物对-二苯氨基联二苯基硼酸(DBBA).用DBBA作为荧光探针,在20%的乙醇水溶液中对各种单糖,如果糖、半乳糖、葡萄糖、甘露糖等进行识别研究,并且计算了DBBA与各种单糖的结合常数.研究结果表明,该新型硼酸衍生物对果糖具有很好的选择性识别.初步探讨了DBBA与果糖、半乳糖、葡萄糖、甘露糖的识别机理,表明DBBA能够识别单糖,DBBA具有分子内电荷转移特性,它与单糖分子结合后不同程度地阻碍了其分子内的电荷转移性质.     

茯苓菌丝体多糖的分离及结构分析

由茯苓菌种在培养基中于 2 5℃下培养一周得茯苓菌丝体 .分别用 0 9%NaCl水溶液、热水、0 5mol/LNaOH和 88%甲酸从该茯苓菌丝体中提取出四种多糖 ,编号为PCM1 ,PCM2 ,PCM3和PCM4 .用红外光谱 (IR) ,高效液相色谱 (HPLC) ,气相色谱 (GC)及13 C 核磁共振 ( 13 C NMR)等方法分析了它们的组成和结构 .结果表明 ,PCM1 ,PCM2为酸性杂多糖由D 鼠李糖、D 木糖、D 甘露糖、D 半乳糖、D 葡萄糖及葡萄糖醛酸组成 .PCM3主要为线型 β ( 1→ 3 ) D 葡聚糖 ,其产率占茯苓菌丝体总量的 55 8% .PCM4由D 葡萄糖和葡萄糖醛酸组成 .茯苓菌丝体化学组成和结构基本同于茯苓菌核多糖 ,随提取过程进行葡萄糖含量逐渐增加的变化规律也相同 .     

肌红蛋白在海藻酸钠水凝胶中的电化学和电催化特性

海藻酸钠(Sodium Alginate,SA)是由L-葡萄糖醛酸与D-甘露糖醛酸组成的高分子线性糖醛酸,常作为固定化酶包埋材料。本文研究了海藻酸钠水凝胶膜中的肌红蛋白在磷酸盐缓冲溶液中的直接电化学和酶催化性质,探讨了测定H2O2和NO2^-的可能性。     

固相酸解法制备古糖酯寡糖及其电喷雾质谱分析

以褐藻酸中分离的聚古罗糖醛酸(PG)为原料, 以三氧化硫-吡啶为硫酸酯化试剂, 采用正交实验法确定了制备高硫酸酯基取代古糖酯(PGS)的最佳工艺条件, 并采用2D-NMR分析对其结构进行了确证. 本文建立了一种新的环境友好型固相酸解方法以制备PGS的寡糖(即采用732#阳离子交换树脂这种固态酸对PGS进行降解). 结果表明, 当732#阳离子交换树脂用量为200 mg/mL、PGS的质量分数为2%时, 在100 ℃下降解6 h可得到重均分子质量(Mw)小于3000的PGS寡糖, 经Bio-Gel P6凝胶层析柱分离可以得到13个聚合度单一的寡糖组分F1~F13. 电喷雾质谱(ESI-MS)分析结果表明, F1~F13分别是聚合度为1~13的PGS寡糖.     

Purification of phospholipase D by two-phase affinity extraction

An aqueous two-phase system of polyethylene glycol (PEG)-salt was used for purification of phospholipase D (PLD) from peanuts and carrots. Alginate, a known macroaffinity ligand for PLD, was incorporated in the PEG phase and resulted in 91 and 93% of the enzyme activity (from peanuts and carrots, respectively) getting partitioned in the PEG phase. The elution of the enzyme from alginate was facilitated by exploiting the fact that the latter can be reversibly precipitated in the presence of Ca2+. The enzyme was eluted from the polymer by using 0.5 M NaCl. Peanuts and carrots PLD could be purified 78- and 17-fold with 82 and 85% activity recovery, respectively. The purified enzyme from both sources gave a single band on sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) electrophoresis.     

Use of different adsorbents for sorption and Bacillus polymyxa protease immobilization

Proteases constitute one of the most important groups of industrial enzymes, accounting for at least 25% of the total enzyme sales, with two-thirds of the proteases produced commercially being of microbial origin (1). Immobilized enzymes are currently the subject of considerable interest because of their advantages over soluble enzymes or alternative, technologies, and the steadily increasing number of applications for immobilized enzymes. The general application of immobilized proteins and enzymes has played a central role in the expansion of biotechnology and synthesis-related industries. Proteases have been immobilized on natural and synthetic supports (2,3). In the present work, a protease from Bacillus polymyxa was partially purified with 80% ammonium sulfate precipitation followed by dialysis and chromatography using a diethylaminoethyl (DEAE)-cellulose ion exchange column. Immobilization was evaluated by using different adsorbents (chitin, chitosan, alginate, synthetic zeolite, and raw zeolite) and the storage stability and recycle of the immobilized protease determined. Immobilization yields were estimated to be 96% and 7.5%, by using alginate and chitosan, respectively, after, 24 h. The yield of the immobilization was 17% for alginate at 16h and the enzyme did not adsorb on the chitin, chitosan, synthetic zeolite, and raw zeolite.     

Isolation of the major O-glycosidically linked oligosaccharides obtained by alkaline borohydride degradation of human meconium glycoproteins

Neutral and acidic oligosaccharides derived from human meconium glycoproteins by alkaline borohydride degradation have been separated by high-performance liquid chromatography on a Micro-Pak anion-exchange column. In each class, oligosaccharides were purified by normal-phase (neutral and acidic oligosaccharides) and reversed-phase (neutral oligosaccharides) chromatography. Effective separations of neutral oligosaccharides and acidic oligosaccharides were achieved.     

Enhanced biodegradation of thiocyanate by immobilized Bacillus brevis

Biodegradation of Thiocyanate by Free and Immobilized Bacillus brevis was explored. Lignite carbon and Alginate beads have been used as immobilization matrices to study the degradation of thiocyanate with immobilized cells. The rate of thiocyanate degradation is found to be higher by immobilized cells. Cells on lignite carbon matrix are more efficient than cells on alginate beads. The tolerance of the bacteria to the toxic chemical increases by immobilization. Degradation of 100 ppm of thiocyanate was achieved in 20 h by immobilized Bacillus brevis onto lignite carbon. Reduced cost and simplicity make this technique very useful for wastewater treatment.     

The flame retardancy of alginate/flame retardant viscose fibers investigated by vertical burning test and cone calorimeter

The smoldering weakness of alginate fibers can be effectively suppressed by simple blending with flame retardant viscose fibers. The char formed by flame retardant viscose fibers can prevent the heat transmission and suppress the smoldering of alginate.     

Improved enzyme retention from an electropolymerized polypyrrole-alginate matrix in the development of biosensors

A novel pyrrole-alginate was synthesized providing a gel by Ca²⁺ cross-linking. The subsequent in situ electrochemical polymerization of the linked pyrrole groups at 0.93 V led to the formation of a composite polypyrrole–gel matrix exhibiting a greater enzyme retention as well as increased alginate stability towards the destructive effect of phosphate anions unlike the natural alginate gel. The presence of the electropolymerized chains was clearly indicated by the decrease of the permeability when compared to natural alginate gel, namely 2.7 × 10⁻² and 3.65 × 10⁻¹ cm s⁻¹ respectively, using as an electroactive permeate, hydroquinone. Moreover, the analytical performance of glucose oxidase-based composite alginate for the determination of glucose was determined.     

Characterization and biodegradation of chitosan-alginate polyelectrolyte complexes

Polyelectrolyte complexes (PECs) have been the focus of an expanding number of studies for their wide use. This study investigated the characteristics and biodegradation of chitosan-alginate PECs prepared by freeze-drying a precipitate from sufficient mixtures of the two polymers. The analyses of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) suggested that the partial protonated amine groups of chitosan reacted with the carboxylate groups of alginate and thus strong PECs were formed. After incubating in lysozyme solution, the PECs showed high ability of enzyme adsorption, and low degradation rate in spite of different degrees of deacetylation of chitosan, due to the strong interaction between chitosan and alginate and the hindrance of closely adsorbed lysozyme.     

Structure and properties of chitosan derivatives modified calcium polyphosphate scaffolds

Organic and inorganic composite material is becoming a solution on making the mechanical and degradation properties of biomaterial more suited. Porous calcium polyphosphate was immersed into different concentrations of carboxymethyl chitosan before immersing 10% alginate dialdegyde. After freeze-drying, the scaffolds were performed in physiologic saline. At stated day, the weightloss, Ca²⁺ concentration, pH value and morphology were measured. The biocompatibility of the composite was demonstrated by extract and direct contact tests. As the results showed, the degradation rates of composites were faster, and the compressive strength became bigger because of the cross-linked network formed by Carboxymethyl chitosan (CMC) and alginate dialdehyde (ADA). The pH value of composite was higher than that of calcium polyphosphate (CPP) due to the organic part of composite’s pH was in slight alkaline. From the SEM, the cross-linked network structure could be observed clearly. Because the glycosaminoglycans-like chains in CMC molecules, which are typically presented in extracellular matrix (ECM), extractions of composite material gave the cells good adhesion and growth condition. All the results testified the composite scaffold was a good candidate for bone repair.